Buy yourself a metal food flask, a large catering pot and some plastic boxes that hold the same as your flask. Make large batches of thick vegetable soup with a real meat base. No rice, pasta or pulses. I make about 15 servings as one go. I buy packets of cooking bacon to make the stock. If you are not a great cook go to the freezer shop. I put carrots, cabbage, leeks, tomatoes and red peppers. Make it thick enough that it is hard to stir. I also add about 4 garlic cloves and some tomato puree. If you freeze in portion sizes it is just a case of taking it out the night before to defrost and heating it up in the morning. Put it on when you are getting showered or having breakfast. I also eat a small potion of meat to help fill me up. There are lots of small tins of tuna and mackerel that are only a few ounces.
If you don't fancy that buy a cool bag and ice blocks and make salads.